1. Field of Invention
The present invention relates to an electrolyte composition, a method of fabricating thereof and a dye-sensitized solar cell using the same. More particularly, the present invention relates to a gel electrolyte composition, a method of fabricating the composition and a dye-sensitized solar cell using the composition. The gel electrolyte composition may optionally be free from or substantially free from one or more of a polymer or a low molecular gelling agent.
2. Description of Related Art
Solar energy is a form of renewable energy available for human consumption in a sustainable manner. It is also a very clean energy source, free from any form of environmental pollution. The effective application of solar energy in a solar cell has been actively pursued by scientists in recent years.
The previous first and second generations of solar cells respectively employ silicon, gallium arsenide as raw materials. The fabrication of silicon is a high energy consumption process, and silicon fabricated at different temperatures affect the conversion efficiency. Hence, solar cells using silicon are deemed non-economical. In addition, arsenic is a type of heavy metal that is highly toxic to the environment.
The third generation solar cells (dye-sensitized solar cells), which are capable of maintaining energy performance and being environmentally friendly, are now being developed. They are safe to use and pollution-free. Further, the temperature range that can be tolerated by dye-sensitized solar cells is larger. Dye-sensitized solar cells are also less sensitive to the incident angle of sunlight and have higher conversion efficiency. Additionally, dye-sensitized solar cells use organic materials that can be rapidly and continuously produced, and the development of these types of material is less confined. Moreover, the cost of a dye-sensitized solar cell using organic materials is about ⅕ to 1/10 of a traditional silicon solar cell. These types of cells are expected to be broadly applied in the fields of 3C and consumer products in the future. Hence, dye-sensitized solar cells are being viewed as the preferred choice of third-generation solar cells.
In 1991, Gratzel applied a nano-titanium dioxide (Nano-TiO2) porous film for fabricating a counter electrode, wherein a ruthenium complex was used as a dye, and iodide ions in the reduction state/iodide ions in the oxidation state (I−/I3−) served as electrolytes. The overall efficiency of a Gratzel cell is up to 7.1%. However, for a dye-sensitized solar cell product, its stability and lifetime are important factors for the product to enter the market. Basically, a dye-sensitized solar cell belongs to the category of electrochemical cells and the presence of an electrolyte is preferred.
A liquid-type electrolyte has a fast diffusion rate, an excellent penetration characteristic, and a high photoelectric conversion efficiency. Further, the components in a liquid-type electrolyte are easily designed or modified. Moreover, the penetration characteristic of a liquid-type electrolyte through a titanium dioxide nano-porous structure is highly desirable. Hence, research on a liquid-type electrolyte is always being pursued. However, when considering the longevity and the commercialization of a cell, since the electrolyte contains a volatile organic solvent, a change in the electrolyte formulation in the cell may potentially result. Ultimately, the dye-sensitized solar cell degrades, reducing the lifetime of the cell. Additionally, the packaging process of a dye-sensitized solar cell is difficult and the stability of the cell is low. If a product package is damaged, the liquid-type electrolyte not only causes cell failure, but the leakage of the liquid also pollutes the environment.